Osteopetrosis: Gene-based nosology and significance Dysosteosclerosis

Dysosteosclerosis (DSS) refers to skeletal dysplasias that radiographically feature focal appendicular osteosclerosis with variable platyspondyly. Genetic heterogeneity is increasingly reported for the DSS phenotype and now involves mutations of SLC29A3, TNFRSF11A, TCIRG1, LRRK1, and CSF1R. Typical radiological findings are widened radiolucent long bones with thin cortices yet dense irregular metaphyses, flattened vertebral bodies, dense ribs, and multiple fractures. However, the radiographic features of DSS evolve, and the metaphyseal and/or appendicular osteosclerosis variably fades with increasing patient age, likely due to some residual osteoclast function. Fractures are the principal presentation of DSS, and may even occur in infancy with SLC29A3-associated DSS. Cranial base sclerosis can lead to cranial nerve palsies such as optic atrophy, and may be the initial presentation, though not observed with SLC29A3-associated DSS. Gene-specific extra-skeletal features can be the main complication in some forms of DSS such as CSF1R- associated DSS. Further genetic heterogeneity is likely, especially for X-linked recessive DSS and cases currently with an unknown genetic defect. Distinguishing DSS can be challenging due to variable clinical and radiological features and an evolving phenotype. However, defining the DSS phenotype is important for predicting complications, prognosis, and instituting appropriate health surveillance and treatment.

Neurological Consequences of Congenital Disorders of Glycosylation

The chapter is devoted to neurological aspects of congenital disorders of glycosylation (CDG). At the beginning, the various types of CDG with neurological presentation of symptoms are summarized. Then, the occurrence of various neurological constellation of abnormalities (for example: epilepsy, brain anomalies on neuroimaging, ataxia, stroke-like episodes, autistic features) in different CDG types are discussed followed by data on possible biomarkers and limited treatment options.

Neurocognitive impairments and brain abnormalities resulting from opioid-related overdoses: A systematic review

BACKGROUND

Non-fatal opioid-related overdoses have increased significantly over the past two decades and there have been increasing reports of brain injuries and/or neurocognitive impairments following overdose events. Limited preclinical research suggests that opioid overdoses may cause brain injury; however, little is known about such injuries in humans. The purpose this systematic review is to summarize existing studies on neurocognitive impairments and/or brain abnormalities associated with an opioid-related overdose in humans.

METHODS

PubMed, Web of Science, Ovid MEDLINE and PsyINFO were searched, without year restrictions, and identified 3099 articles. An additional 24 articles were identified by reviewing references. Articles were included if they were published in English, reported study findings in humans, included individuals 18 years of age or older, and reported an objective measure of neurocognitive impairments and/or brain abnormalities resulting from an opioid-related overdose. Six domains of bias (selection, performance, attrition, detection (two dimensions) and reporting were evaluated and themes were summarized.

RESULTS

Seventy-nine journal articles, published between 1973-2020, were included in the review. More than half of the articles were case reports (n = 44) and there were 11 cohort studies, 18 case series, and 6 case-control studies. All of the studies were categorized as at-risk of bias, few controlled for confounding factors, and methodological differences made direct comparisons difficult. Less than half of the studies reported toxicology results confirming an opioid-related overdose; 64.6 % reported brain MRI results and 27.8 % reported results of neuropsychological testing. Only two studies had within subject comparative data to document changes in the brain possibly associated with an overdose. Despite these limitations, existing publications suggest that brain injuries and neurocognitive impairments are associated with opioid overdose. Additional research is needed to establish the incidence of overdose-related brain injuries and the potential impact on functioning, as well as engagement in treatment of substance use disorders.

CONCLUSIONS

Respiratory depression is a defining characteristic of opioid overdose and prolonged cerebral hypoxia may cause brain injuries and/or neurocognitive impairments. The onset, characteristics, and duration of such injuries is variable and additional research is needed to understand their clinical implications.

Brain imaging in patients with COVID-19: A systematic review

Background

There is increasing evidence that SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) not only affects the respiratory tract but also influence the central nervous system (CNS), resulting in neurological symptoms such as loss of smell and taste. Growing literature indicates largely distributed brain alterations encompassing subcortical micro- and macro-bleeds, cerebral swelling and haemorrhage in gray and white matter tissue. A systematic review was performed to synthesise the potential evidence of the brain correlates of SARS-CoV-2.

Methods

A literature search was conducted using electronic databases for studies reporting neuroimaging abnormalities in SARS-CoV-2 infected individuals. Identified case series, cohort studies, and case control studies on SARS-CoV-2 effects on the brain were critically appraised for methodological quality. A narrative synthesis of the findings from the included studies is presented.

Results

Twenty-seven studies were included in the review, including 5 case series, 8 cohort studies and 14 case control studies. The findings revealed predominant involvement of the olfactory system with disruptions across four olfactory structures. Abnormalities also extended to the corpus callosum, cingulate cortex, and insula, jointly implicating the olfactory brain network.

Conclusion

Alterations in olfactory areas, along with neighbouring brain regions, including prefrontal and limbic regions were associated to contraction of SARS-CoV-2. Viral infection could either trigger systemic reactions, or use the olfactory's unique anatomical organisation as an environmental entry zone to directly impact on the CNS.

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A spectrum of brain changes particularly at advanced stage relates to SARS-CoV-2

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Across severity phases SARS-CoV-2 affects olfactory structures

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Emerging abnormalities in COVID-19 is associated with the olfactory brain network

MRI imaging of prenatal-postatal brain malformations

A fetus with suspicion for holoprosencephaly and various brain malformations were seen on ultrasound and send for magnetic resonance imaging (MRI). Immediately after the birth of the female patient ultrasound and MRI was made which confirmed lobar holoprosencephaly. Fetal MRI stands out as a powerful diagnostic tool for detecting anomalies and other disorders. By developing new sequences and raising image quality will enable visualization of small details.

Kabuki syndrome: novel pathogenic variants, new phenotypes and review of literature

Objective

This study describes 5 novel variants of 7 KMT2D/KDM6A gene and summarizes the clinical manifestations and the mutational spectrum of 47 Chinese Kabuki syndrome (KS) patients.

Methods

Blood samples were collected for whole-exome sequencing (WES) for 7 patients and their parents if available. Phenotypic and genotypic spectra of 40 previously published unrelated Chinese KS patients were summarized.

Result

Genetic sequencing identified six KMT2D variants (c.3926delC, c.5845delC, c.6595delT, c.12630delG, c.16294C > T, and c.16442delG) and one KDM6A variant (c.2668-2671del). Of them, 4 variants (c.3926delC, c.5845delC, c.12630delG, and c.16442delG) in KMT2D gene and the variant (c.2668-2671del) in KDM6A gene were novel. Combining with previously published Chinese KS cases, the patients presented with five cardinal manifestations including facial dysmorphism, intellectual disability, growth retardation, fingertip pads and skeletal abnormalities. In addition, 29.5% (5/17) patients had brain abnormalities, such as hydrocephalus, cerebellar vermis dysplasia, thin pituitary and white matter myelination delay, corpus callosum hypoplasia and Dandy-Walker malformation.

Conclusion

In this report, five novel variants in KMT2D/KDM6A genes are described. A subset of Chinese KS patients presented with brain abnormalities that were not previously reported. Our study expands the mutational and phenotypic spectra of KS.

Neuroimaging assessment in Down syndrome: a pictorial review

Down syndrome (DS), or trisomy 21, is the leading genetic cause of intellectual incapacity worldwide, with a reported incidence of about 1 in 1,000 to 1 in 1,100 live births. Besides the several commonly known physical features characteristic of this syndrome present at birth, DS may additionally affect every organ system. In addition, despite the large number of published papers concerning this syndrome, there is scarce literature focusing specifically in the typical neuroimaging features associated with this condition. The aim of this paper is to review and systematize the distinctive characteristics and abnormalities of the central nervous system, head and neck, and spine present in DS patients that should actively be searched for and evaluated by radiologists and/or neuroradiologists.

Neuroimaging findings associated with congenital Zika virus syndrome: case series at the time of first epidemic outbreak in Pernambuco State, Brazil

PURPOSE

This study aimed to describe the prenatal and postnatal neuroimaging and clinical findings in a clinical series following congenital Zika virus syndrome during the first epidemic Zika virus (ZIKV) outbreak in the State of Pernambuco, Brazil.

METHODS

We (the authors) conducted a retrospective study of a prospectively collected case series of fetuses and neonates with microcephaly born to mothers with presumed/confirmed congenital ZIKV syndrome. Prenatal ultrasound findings were reviewed to identify potential central nervous system (CNS) abnormalities. Neonates underwent postnatal neuroimaging follow up by computed tomography (CT)-scan or magnetic resonance (MR) imaging.

RESULTS

The prenatal and postnatal outcomes of eight fetuses/neonates born to mothers with presumed/confirmed congenital ZIKV syndrome were examined. The mean gestational age at ultrasound was 31.3 weeks. Severe microcephaly was identified in seven fetuses (87.5%), while ventriculomegaly and brain calcifications were detected in all fetuses. The mean gestational age at delivery and head circumference were 38 weeks and 30.2 cm, respectively. All cases of microcephaly but one was confirmed postnatally. Brain CT scans or MRIs were performed in seven newborns, and all had periventricular and/or parenchymal calcifications, symmetrical or asymmetrical ventriculomegaly, pachygyria, and reduced sulcation and gyration. MR imaging aided the detection of one undetected case of corpus callosum dysgenesis and was essential in documenting reduced mantel of the cerebral cortex and reduced gyration and sulcation, especially involving the parietal lobe. In addition, MR imaging was also able to display irregular interfaces with the subcortical white matter, a finding consistent with polymicrogyria, more frequently seen at the level of the frontal lobe and atrophic and thinned pons.

CONCLUSION

Severe microcephaly and CNS abnormalities may be associated with congenital ZIKV syndrome.

Grey matter volume and thickness abnormalities in young people with a history of childhood abuse

BACKGROUND

Childhood abuse is associated with abnormalities in brain structure and function. Few studies have investigated abuse-related brain abnormalities in medication-naïve, drug-free youth that also controlled for psychiatric comorbidities by inclusion of a psychiatric control group, which is crucial to disentangle the effects of abuse from those associated with the psychiatric conditions.

METHODS

Cortical volume (CV), cortical thickness (CT) and surface area (SA) were measured in 22 age- and gender-matched medication-naïve youth (aged 13-20) exposed to childhood abuse, 19 psychiatric controls matched for psychiatric diagnoses and 27 healthy controls. Both region-of-interest (ROI) and whole-brain analyses were conducted.

RESULTS

For the ROI analysis, the childhood abuse group compared with healthy controls only, had significantly reduced CV in bilateral cerebellum and reduced CT in left insula and right lateral orbitofrontal cortex (OFC). At the whole-brain level, relative to healthy controls, the childhood abuse group showed significantly reduced CV in left lingual, pericalcarine, precuneus and superior parietal gyri, and reduced CT in left pre-/postcentral and paracentral regions, which furthermore correlated with greater abuse severity. They also had increased CV in left inferior and middle temporal gyri relative to healthy controls. Abnormalities in the precuneus, temporal and precentral regions were abuse-specific relative to psychiatric controls, albeit at a more lenient level. Groups did not differ in SA.

CONCLUSIONS

Childhood abuse is associated with widespread structural abnormalities in OFC-insular, cerebellar, occipital, parietal and temporal regions, which likely underlie the abnormal affective, motivational and cognitive functions typically observed in this population.

Integrating molecular and structural findings: Wnt as a possible actor in shaping cognitive impairment in Cornelia de Lange syndrome

Cornelia de Lange Syndrome (CdLS) is a choesinopathy: a severe genetic disorder caused by mutations in the cohesin complex genes. The phenotype is characterized by typical facial dysmorphism, growth impairment and multiorgan abnormalities including brain alterations. Wnt pathway is known to play a fundamental role in central nervous system development and it has been shown that Wnt pathway is disrupted in CdLS animal models and patients cells. In this review we investigate the possible link between Wnt pathway disruption and brain abnormalities in Cornelia de Lange Syndrome as such molecular impairment could lead to an abnormal embryonic development resulting in brain abnormalities (i.e. microcephaly, cerebellar hypoplasia, abnormal cortical development) in patients with Cornelia de Lange Syndrome.

Ultrasonographic observations of the fetal brain in the first 100 pregnant women with Zika virus infection in Trinidad and Tobago

OBJECTIVE

To evaluate the fetal brain in pregnant women infected with Zika virus in a limited-resource setting.

METHODS

In an observational study in Trinidad and Tobago, 100 pregnant women infected with Zika virus who were referred for fetal medicine services provided by a single clinician were enrolled from March 31 to September 2, 2016. Two-dimensional ultrasonography was undertaken.

RESULTS

The women were aged 17-41 years (mean 27.5 ± 5.7). Six cases of fetal brain abnormalities consistent with Zika infection were detected before 26 gestational weeks. The gestational period at infection and time of presentation ranged, respectively, from 7⁺³ to 16⁺⁰  weeks and from 23⁺² to 25⁺⁵  weeks. In all cases, centiles of the biparietal diameter and head circumference decreased progressively over time to below the third centile. The skull contour appeared irregular, owing to collapse or overlap of the fetal skull bones. In four cases, brain anomalies were not obvious on the transabdominal scan but were diagnosed on the transvaginal scan. In a further two cases, brain abnormalities presented after 26 weeks of gestation.

CONCLUSION

Overall, 8.0% of women infected with Zika virus had fetuses with brain abnormalities suggestive of Zika congenital syndrome. Six cases were detected before 26 weeks and two cases after 26 weeks.

Language comprehension in nonspeaking children with severe cerebral palsy: Neuroanatomical substrate?

BACKGROUND AND AIMS

To identify relations between brain abnormalities and spoken language comprehension, MRI characteristics of 80 nonspeaking children with severe CP were examined.

METHODS

MRI scans were analysed for patterns of brain abnormalities and scored for specific MRI measures: white matter (WM) areas; size of lateral ventricles, WM abnormality/reduction, cysts, subarachnoid space, corpus callosum thinning and grey matter (GM) areas; cortical GM abnormalities, thalamus, putamen, globus pallidus and nucleus caudatus and cerebellar abnormalities. Language comprehension was assessed with a new validated instrument (C-BiLLT).

RESULTS

MRI scans of 35 children were classified as a basal ganglia necrosis (BGN) pattern, with damage to central GM areas; in 60% of these children damage to WM areas was also found. MRI scans of 13 children were classified as periventricular leukomalacia (PVL) with little concomitant damage to central GM areas, 13 as malformations and 19 as miscellaneous. Language comprehension was best in children with BGN, followed by malformations and miscellaneous, and was poorest in PVL. Linear regression modelling per pattern group (malformations excluded), with MRI measures as independent variables, revealed that corpus callosum thinning in BGN and parieto-occipital WM reduction in PVL were the most important explanatory factors for poor language comprehension. No MRI measures explained outcomes in language comprehension in the miscellaneous group.

CONCLUSIONS

Comprehension of spoken language differs between MRI patterns of severe CP. In children with BGN and PVL differences in language comprehension performance is attributed to damage in the WM areas. Language comprehension was most affected in children with WM lesions in the subcortical and then periventricular areas, most characteristic for children with PVL.